From: David Ahern <dsahern@gmail.com>
To: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: PEBS (in perf) stopped working from 3.6 -> 3.7
Date: Sun, 06 Jan 2013 20:48:36 -0700 [thread overview]
Message-ID: <50EA4594.9020309@gmail.com> (raw)
In-Reply-To: <20130105010501.GA5371@uio.no>
On 1/4/13 6:05 PM, Steinar H. Gunderson wrote:
> On Fri, Jan 04, 2013 at 05:16:27PM -0700, David Ahern wrote:
>> Known problem. Pick one of: update perf to 3.7, add H to the command
>> (-e cycles:ppH) or apply this patch:
>> https://lkml.org/lkml/2012/12/28/384
>
> I spoke too soon. This works for cycles, but not for branch-misses:
>
> pannekake:~> sudo perf record -e branch-misses:ppH -a
>
> Error: sys_perf_event_open() syscall returned with 95 (Operation not supported) for event branch-misses:ppH. /bin/dmesg may provide additional information.
>
> No hardware sampling interrupt available. No APIC? If so then you can boot the kernel with the "lapic" boot parameter to force-enable it.
>
> Why would the two be different?
I will make a guess that is processor dependent. On an E5540 with
3.4.11-1.fc16.x86_64, 3.6.10-2.fc16.x86_64, and 3.8 I get the same
failure message.
But on a E5620, it works fine with 3.4 and 3.7 (no intermediate kernels
on that box).
David
next prev parent reply other threads:[~2013-01-07 3:48 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-04 23:47 PEBS (in perf) stopped working from 3.6 -> 3.7 Steinar H. Gunderson
2013-01-05 0:16 ` David Ahern
2013-01-05 0:21 ` Steinar H. Gunderson
2013-01-05 1:05 ` Steinar H. Gunderson
2013-01-07 3:48 ` David Ahern [this message]
2013-01-07 14:40 ` Steinar H. Gunderson
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